As a simple dry process for obtaining images, particularly full color images, there is known a method which uses a heat sensitive transfer material. In such a heat sensitive material, a dye used to form color images is of especial importance, and there have been proposed a variety of dyes for this purpose. The dye for color image formation is required to have good absorption characteristics including a sharp spectral absorption less in secondary absorption and a high spectral absorption coefficient as well as high stabilities to heat and light. Further, it is also important that the dye can be easily synthesized and readily dissolved in a solvent. Japanese Pat. O.P.I. Pub. No. 63194/1989 proposes a heat transfer material which uses a specific magenta dye. The heat sensitive transfer material which uses the dye disclosed in the above patent can form images of good hue and, further, has a high sensitivity because the dye itself has a high molar absorption coefficient, so that the pending problems of heat sensitive image transfer can be solved in those respects. However, it has a defect that the light fastness of images is considerably low. With the object of eliminating the defect in light fastness, Japanese Pat. O.P.I. Pub. No. 178646/1992 proposes a pyrazoloazole azomethine dye having a specific atomic group in its dye structure and a heat sensitive transfer material using the dye. However, the dye disclosed in said patent has disadvantages that its synthesis needs a complicated procedure and that when used in a heat sensitive material, it lowers the sensitivity because of its large molecular weight due to an atomic group introduced into it.